The method of forming patterns such as letters, symbols and shapes on the surface of the metal object of the metal ornaments, such as rings or pendants, will be explained. Namely, there is a method of forming pattern on the metal surface by stamping and engraving. There is another method of forming pattern by corroding the pattern parts or non-pattern parts on the metal surface. These methods form the pattern on the surface of the metal object by varying the height of the surface of the metal object of non-pattern parts and pattern parts.
As an alternative, to form the patterns, fitting metal parts made of different materials into the concave of pattern parts formed by stamping, or pouring molten metal of different materials into the concave (reference: Patent Document 1). This method is to form the patterns on the surface of the metal object using differences in colors and luster between the metal object pattern formed on the surface and the metals fitting or pouring into the concave to make patterns.
The aforementioned method of pattern forming using difference of colors is differ from the method of pattern formation by differentiate the heights of the surface of the metal object. The heights of the surface of the metal object are definite after patterns formed and maintaining a plane of the surface of the metal. Therefore, the latter method has a different aesthetic from a method forming patterns by differentiate the heights of the surface.
However, a method of inserting the metal parts patterned shape is required high machining accuracy in the process of the pattern forming. Also, machining accuracy is limited, therefore it is difficult to form patterns with high aesthetic on the surface of the metal. Furthermore, when the patterns are complex, the method of pouring molten metal is difficult to form the precise patterns because the metals are not able to be poured in the detail of the pattern shape concave. Therefore, it is difficult to form patterns with high aesthetic on the surface of the metal object.